Impregnated cellulosic sheet members wherein impregnant is a c{11 {14 c{11 {11 carbocyclic substituted resole

ABSTRACT

Cellulosic substrates impregnated with a phenol-formaldehyde resin using a phenol which has been previously substituted with a specific C8 through C13 mixture of carbocylic compounds. The resulting impregnated sheets display an improved combination of properties including good tensile strength and flexibility, and are especially useful as filter media and as intermediates for the manufacture of laminates.

United States Patent Anderson et al.

Inventors: George J. Anderson, Wilbraham; Ronald Assignee:

Notice:

Dahms, Springfield, both of Mass.

Monsanto Company, Saint Louis, M0.

The portion of the term of this patent subsequent to Oct. 16, 1988, has been disclaimed.

Filed:

June 21, 1968 Appl. No.: 738,797

Related U.S. Application Data Continuation-impart of Ser. No. 588,310, Oct. 21, 1966, abandoned.

U.S.Cl. ..ll7/143A,117/132 BF, 117/138.8 A, 117/148, 117/155 L, 117/161 L, 161/259, 161/262, 161/264, 260/293, 260/32.8 R, 260/334 R,

Int. Cl.

Field of Search 260/336 R, 260/51 R, 260/53 R ..C08g 5/08, C08g 37 10, C08g 37/18 ..260/5l,57,59; 117 155 L, 117/143 A [451 *Jan. 25, 1972 [5 6] References Cited UNlTED STATES PATENTS 3,549,576 12/1970 Anderson et al ..260/29.3

Primary Examinerl-loward E. Schain Attorney-J. W. Klooster, Arthur E. Hoffman and H. B. Roberts [5 7] ABSTRACT Cellulosic substrates impregnated with a phenol-formaldehyde resin using a phenol which has been previously substituted with a specific C through C mixture of carbocylic compounds. The resulting impregnated sheets display an improved combination of properties including good tensile strength and flexibility, and are especially useful as filter media and as intermediates for the manufacture of laminates.

9 Claims, No Drawings IMPREGNATED CELLULOSIC SHEET MEMBERS WHEREIN IMPREGNANT IS A C C CARBOCYCLIC SUBSTITUTED RESOLE RELATED APPLICATIONS This application is a continuation-in-part of our copending applications Ser. No. 588,310, filed Oct. 21, 1966; Ser. No. 605,604, filed Dec. 29, 1966; Ser. No. 676,043, filed Oct. 18,

1967, Ser. No. 676,039 filed Oct. 18, 1967, and Ser. No. 1

676,062, filed Oct. 18, 1967, all now abandoned.

BACKGROUND In the art of impregnating cellulosic substrate members in a sheetlike form with phenolic resins, it has long been appreciated that phenol-formaldehyde resins tend to make impregnated cellulosic substrate members which, when impregnated with sufficient such resin to have acceptable strength, have strong tendencies to be brittle.

When such an impregnated substrate member is used to make filter media (for example, oil filters used with internal combustion engines, and the like), a so-impregnated substrate member is heated to a temperature sufficient to thermoset the resin and produce a porous, relatively stiff product. Unless there is a careful balance of properties in such a product, especially a suitable combination of porosity, tensile strength, and flexibility, the product filter medium is of low quality. For example, it may become brittle when exposed to hot motor oil.

Similarly, when such an impregnated substrate member is used to make laminates (for example, laminates for use as a circuit board or terminal board in electrical applications, or the like), so-impregnated substrate members are arranged into a multilayered configuration and thermoset together under heat and pressure to form a desired laminate. Here again, unless there is a careful balance of properties in such a laminate, especially a combination of good electrical properties and low-water absorption, the product laminate is of poor quality. For example, it may tend to become dimensionally unstable and have poor electrical properties under humid conditions.

There has now been discovered a new and very useful class of resin impregnated cellulosic substrates in which the impregnating resin is a certain substituted phenol-formaldehyde resole resin. Depending upon the type of cellulosic substrate employed, and upon the amount and particular type of such substituted phenol-formaldehyde resin employed, the product nonthermoset resin-impregnated cellulosic substrates can be used as intermediates in a wide variety of articles of manufacture, such as filters, laminates, and the like. Usually, such intermediates are therrnoset in making the final articles. The product articles generally and characteristically have an improved combination or balance of properties, including good tensile strength and flexibility. Particular articles can be prepared having improved filter characteristics and/or improved electrical characteristics.

SUMMARY This invention is directed to resin impregnated sheetlike forms comprising cellulosic substrates which are each impregnated with from about 5 to 70 weight percent (based on total weight) of at least one substituted phenol-formaldehyderesole resin.

The phenol-formaldehyde resole resin employed in the products of this invention has a formaldehyde to phenol mol ratio of from about 0.8 to 2.0 (preferably from about 0.9 to 1.5), and is produced by reacting in the presence of a basic (preferably organic) catalyst under liquid aqueous phase conditions a certain substituted phenol mixture with formaldehyde. The resole resin used in this invention further has a relatively high-molecular weight as shown by the fact that it is,

substantially water insoluble but has a methanol solubility such that a 60 weight percent solution thereof can be prepared in methanol. Such methanol solution characteristically has a viscosity not greater than about 5,000 centipoises', and preferably in the range from about 50 to 500 centipoises. In addition, this resin has a free formaldehyde content which is less than about 5 weight percent.

It will be appreciated that the aldehyde to phenol ratios herein described have reference to the total amount of phenol present before a reaction, including the phenol which is substituted.

The substituted phenol mixture used to make such resin is itself prepared by reacting phenol under Friedel-Crafts conditions with a controlled mixture of carbocyclic compounds. The mixture of carbocyclic compounds comprises (on a weight percent basis when in a form substantially free of other materials):

A. from about 10 through 40 weight percent of compounds, each molecule of which has:

1. the indene nucleus,

2. from nine through 13 carbon atoms,

3. as nuclear subs,itutents from 0 through 4 methyl groups,

B. from about 5 through 70 weight percent of compounds, each molecule of which has:

1. the dicyclopentadiene nucleus,

2. from about 10 through 13 carbon atoms,

3. as nuclear substitutents from 0 through 3 methyl groups,

C. from about 15 through 65 weight percent of compounds, each molecule of which has:

1. a phenyl group substituted by a vinylidene group,

2. from about eight through 13 carbon atoms,

3. as substituents from 0 through 3 groups selected from the class consisting of methyl and ethyl,

D. from about 0 through 5 weight percent divinyl benzene,

E. provided that the sum total of all such compounds in any given such mixture of carbocyclic compounds is always 100 weight percent.

At the time when such controlled mixture of carbocyclic compounds is reacted with phenol as indicated, there can be present in such mixture as diluents inert (i.e., as respects reactivity towards phenol under Friedel-Crafts reaction conditions) organic compounds such as aromatic and aliphatic hydrocarbons. Thus, there is present, conveniently, at least about 25 weight percent of diluent in such total combination of mixture of carbocyclic compounds and diluent, although this value is variable depending upon reactants and reaction conditions. While there is no apparent upper limit on the amount of diluent which may be present, it is preferred that the amount of diluent present be not greater than about 95 weight percent (same basis). Preferably, the amount of diluent ranges from about 15 to 70 weight percent (same basis). Up to about 10 weight percent (same basis) of water can be present, but it is preferred to use substantially anhydrous conditions.

Carbocyclic compound mixtures useful in this invention are available commercially from various petroleum producers under a variety of trade names. For examples, one suitable carbocyclic compound mixture is available from Enjay Chemical Company under the trade designation Heart Cut LPD." Another suitable such mixture is available from Monsanto Company, St. Louis, Missouri, under the trade designation Resin Oil." Still another such mixture is available from the Gulf Oil Company under the trade designation Resin Former Feed Stock. A presently preferred such mixture is the Monsanto Company Resin Oil" which is a C to C product out with a boiling range of from about 300 to 425 F. to about 220 C.) and contains the indicated carbocyclic compound mixture. Shown below in table 1 is a breakdown such as is made by vapor phase chromatography show ing the composition of these three carbocyclic compound mixtures.

TAeLET Gulf Oil 2 Monsanto 3 Eniay vinylidene aromatics:

tyrene o, 7.6 1. 4 10.1 ..A fa ls-met yl yrsnsa$311.:ar A.. .iJL... -2

By the term dicyclopentadiene reference is had to a molecule having the structure:

By the phrase when in a form substantially free of other materials" reference is had to a mixture (e.g., of starting materials, of products, or the like, as the case may be) which is substantially free (cg, on an analytical or a theoretical basis) of substances (like inerts) other than such mixture itself. For example, in table I above, the carbocyclic compound mixtures are composed of indenes, vinylidene aromatics, and dicyclopentadienes as well as inert diluents, such as alkyl aromatics." napthalenes and "unidentified aliphatics," but each contains a combination (on a I weight percent basis in a form substantially free of other materials) of components (indenes, dicyclopentadiene, and vinylidene aromatics) as described above.

in this invention, all solids are conveniently measured using the ASTM Test Procedure Dl l-55.

Also in such a preferred embodiment, the substituted phenol used in making phenolic resin is made using a carbocyclic compound mixture in which there are from about through 40 weight percent of compounds having the indene nucleus (as above described), from about l5 through weight percent of compounds having the dicyclopentadiene nucleus (as above described) and from about 30 through 65 weight percent of compounds having a phenyl group and a vinylidene group as above described, the percentage of divinyl benzene in such preferred carbocyclic compound mixture being as described above. in any such more preferred carbocyclic compound mixture, there are a total of 100 weight percent of these three components The term vinylidene" as used herein has generic reference both to vinylidene radicals CIIFC and vinyl radicals TABLE I -(ontmued Gull Oil 2 Monsanto Enjoy lietwmethylstyrene Cu 1.5 1.0 2. l Vinyltolucno Ca 4. 5 17. 4 10. 5 alkylstyrene 1 C10 0.1) 2.0 5.8 Divinylbenzenc C 0 0.3 1.3 1.0 lndenvs:

lndcne C 12.7 17. 0 12. 7 Methylludone C10 i. 0.3 5. 5 7 6 (lyclopentadienes:

lsoprene-eyclopentadieno C1 0.6 0.3 Dicyclopentadicne Cm 42. 7 13. l) 1,1 ltlethylcyclopentadiene C 12.4 4. 6 2.1 Alkyl aromatics:

Benzene Cl; 0. 5 0.1 Toluene C A. 3. 9 .1 0.8 C; ulkylbenzeno C3 7. 4 0. 4 12. 1 .1 alkylbenrcne C 1.2 19.2 22. 2 Cl alkylbenzeno O10 4.1 6.3 Na hthalenes: Naphthalene Cu"... 0.2 3.2 2.2 Un dentified (aliphatics) .1 2.1 Total carbocyclic compound mixture contcnt 84. 8 72, 6 55. 9 ASTM boil range, F. (ASTM D-86):

Initial boiling point 283 315 307 10%. 318 333 320 320 343 342 348 367 401 11364 402 411 0 Specific gravity 0. 952 0. 933 0. 900

1 This styrene compound is selected from the group consisting of o j .yrene and dimethylstyi'cne.

1 Available commercially from the Gulf Oil Company as Resin Former Stock." 1 Available commercially from Monsanto Co. under the trade designa. ion Resin 00.))" g Available commercially from Enjay Co. under the trade designation Heart Cut LPD."

To react phenol with such an aforedescribed carbocyclic compound mixture, it is convenient to use Friedel-Crafts conditions, as indicated.

The term Fn'edel-Crafts conditions" as used herein refers to the conventional conditions known to those of ordinary skill in the art used for the alkylating or arylating of hydrocarbons (including phenol) by the catalytic action of aluminum chloride or equivalent acid catalyst in the presence of appropriate heat and pressure. Conveniently, the phenol and suitable Friedel-Crafts acid catalyst are mixed, brought to the proper temperature and the carbocyclic compound mixture metered into the acidified (or catalyzed) phenol.

For purposes of this invention, the reaction of carbocyclic compound mixture with phenol is preferably carried out at temperatures in the range of from about 25 to 200 C., although higher and lower temperatures can be used. Also, the reaction is preferably conducted under liquid phase conditions at or below atmospheric pressures although superatmospheric pressures can be used. inert hydrocarbons, as indicated above, generally facilitate the process. Such inert hydrocarbons, can be readily removed, such as by vacuum stripping, at the completion of the reaction if desired. Especially when stripping is contemplated, the most preferred inert hydrocarbons have boiling points between about 70 and 140 C. The progress of the reaction can be monitored, if desired, by measuring the quantity remaining of unreacted carbocyclic compound mixture using, for example, vapor phase chromatography.

Friedel-Crafts catalysts which may be used in place of aluminum chloride, or together with aluminum chloride, include:

A. other inorganic halides, such as gallium, titanium, antimony and zinc halides (including ZnCl B. inorganic acids such as sulphuric, phosphoric and the df i 'l ?f jd. fl F a,

C. activated clays, silica gel and alumina;

D. BE, and BE, organic complexes, such as complexes of BF with organic compounds, such as ethanol, butanol, glycol, phenol, cresol, anisole, ethyl ether, isopropyl ether, di-n-butyl ether, formic acid, acetic acid, propionic acid, and the like, or with inorganic acids, such as phorphoric acid, sulfuric acid, w dths i"! a H E. alkyl, aryl, and aralkyl sulfonic acids, such as ethane-sulfonic acid, benzene sulfonic acid, benzene disulfonic acid, chlorobenzene sulfonic acid, 3,4-dichlorobenzene sulfonic acid, cresol sulfonic acids, phenol sulfonic acids, toluene sulfonic acids, xylene sulfonic acids, octylphenol sulfonic acid, B- naphthalene sulfonic acid, l-naphthol-4-sulfonic acid, and the like. When BF as such, is employed, it is conveniently fed to a reaction mixture in gaseous form.

While any combination of carbocyclic compound starting mixture, phenol and catalyst can be used, it is particularly convenient to react in the presence of less than about weight percent (based on the phenol) of acid catalyst.

The reaction mass is heated to a temperature in the range of from about to 200 C. The rate of this reaction is dependent, to some degree, on the temperature employed. In general, the reaction is rapid, and a complete reaction between phenol and carbocyclic compound mixture is preferred. Generally a heating time of from about 10 minutes to 4 hours is employed. The various process variables are summarized in table ll below.

TABLE II Process variable Broad range Preferred range Temperature About 25 to 200 0.- About to 125 0. Reaction time Less than about 4 About 10 to 30 min.

hours. Catalyst (based on phenol)- Less than about 10 About 0.1 to 1.0

Weight percent. weight percent.

1 On a 100 weight percent basis, when in a form substantially free of othgr materials. v

The properties of a given so-substituted phenol product are affected by the process conditions used to make that product (e.g., molecular weight distribution, color and the like). The resulting reaction product is, as those skilled in the art will appreciate, a complex mixture of various different substituted phenols produced from the reaction of phenol under Friedel- Crafts conditions with the carbocyclic compound starting mixture to product phenol molecules which are substituted both on ring carbon atoms and on phenol hydroxyl oxygen atoms by moieties derived from such carbocyclic compound.

A substituted carbocyclic compound phenol product can be prepared in a form substantially free of starting materials by conventional distillation separation techniques (e.g., steam distillation, vacuum stripping, and the like), as those skilled in the art will appreciate, but in making resoles for use in this invention, such product can be used directly as made.

In general, to produce a resole for use in this invention, a substituted phenol product, as just described, is neutralized under aqueous liquid phase conditions as by the addition of base, and then from about 0.8 to 2.0 mols of formaldehyde per 1 mol of phenol (preferably from about 1.0 to 1.5 mols aldehyde per mol of phenol) is mixed with the substituted phenol product (now itself a starting material). Water may be added with the formaldehyde. Formalin is preferred as a source for formaldehyde. Also, a basic catalyst material, such as hexamethylenetetramine, ammonium hydroxide, triethylamine, sodium hydroxide, or mixtures thereof (or the like) is introduced into the reaction mixture. This basic catalyst can be used to neutralize the starting substituted phenol. The pH of this reaction mixture is maintained above 7.0 and preferably in the range of from 7.5 to 8.5. This reaction mixture is then heated to temperatures of from about to 100 C. for a time sufficient to substantially react most of the formaldehyde and produce a desired resole product. Times of from about 20 to 140 minutes are typical. Aqueous liquid phase preparation conditions are generally but not necessarily used.

To optimize electrical properties in resoles used in this invention, it is preferred to use as a basic catalyst, when reacting such substituted phenols with formaldehyde to make resole resins, one which is organic in character.

The resole product produced by reacting the substituted phenol with formaldehyde as described above is one composed of methylolated substituted phenol which has been methylolated by the aldehyde to a desired methylol content and optionally advanced (e.g., the molecular weight of the methylolated substituted phenol increased) as by heating as necessary or desirable to make a particular resole product. As those skilled in the art fully appreciate, the methylol content and the degree of advancement are controllable so that one can optimize such a resole resin for use in a particular application. For purposes of this invention, a phenol-formaldehyde resole resin or resole can be regarded as being the reaction product of the above-described substituted phenol mixture and formaldehyde under aqueous base catalyzed conditions as described herein which product can be thermoset by heat alone without the use of a curing catalyst.

In general, such a resole product as made is a brown colored, unstable, multiphase aqueous emulsion whose viscosity depends, in any given instance, upon process and reactant variables but which usually ranges from a syrupy liquid to a semisolid state. Such a resole product usually separates from such aqueous phase as a brown colored material whose viscosity varies from a syrup to a solid. For use in the present invention, such a resole product is preferably prepared as a varnish.

To make a resole resin varnish for use in this invention, such an emulsion is dehydrated preferably under heat and reduced pressure to a water content of from about 0.5 to 15 weight percent. After such dehydration, the resulting resin is then dissolved in a relatively volatile, inert organic solvent medium which:

1. is substantially inert,

2. evaporate below about 150 C. at atmospheric pressures,

and

3. is a mutual solvent for said resole resin and water (if present) While the organic liquid used has properties as indicated above, it will be appreciated that such liquid can comprise mixtures of different organic liquids. Preferred liquids are lower alkanols (such as ethanol and methanol) and lower alkanones (such as acetone or methyl ethyl ketone). The term lower" refers to less than seven carbon atoms per molecule as used herein. Aromatic and aliphatic (including cycloaliphatic) hydrocarbons can also be employed as solvents for a given resin, including benzene, toluene, xylene, naphthalene, nonone, octane, petroleum fractions, etc. Preferably, the total water content of a varnish of the invention is below about 10 weight percent, and more preferably falls in the range of from about 0.5 to 5 weight percent.

Those skilled in the art will appreciate that care should preferably be taken when using this procedure to use an organic liquid system in which the phenolic resole resins are completely soluble as well as any water present. Adding, for example, a ketone or an ether-ester solvent like butyl cellosolve will generally improve the water tolerance (ability to dissolve water) of a solvent system.

These varnishes are characteristically dark colored, onephase, clear liquid solutions each having a viscosity ranging from about 5-5 ,000 centipoises. The exact viscosity of a given varnish depends upon many chemical process and product variables. For impregnating applications, viscosities of from about 50 to 500 centipoises are preferred.

The total solids content of a given varnish can be as high as about weight percent or even higher and as low as about 20 weight percent or even lower, but preferred solids contents usually fall in the range of from about 25 to 65 weight percent.

The resole varnishes used in this invention thus comprise:

A. from about 20 to 75 weight percent of a dissolved mixture of a phenol formaldehyde resole resin,

B. from about 0.5 to 15 weight percent of dissolved water,

C. the balance up to weight percent of any given varnish being an organic liquid having properties as described above.

In general an individual cellulosic substrate used in the present invention as in a preformed sheetlike condition and need have no special characteristics. It can be composed of cellulosic fibers which optionally can obtain up to about 50 weight percent of a synthetic organic polymeric fibrous material, such as a polyester, a polyimide, a vinylidene chloride polymer, and acrylonitrile/vinyl chloride copolymer, mixtures thereof, and the like. Typical thicknesses range from about 3 to 30 mils (under about 10 preferred). The cellulosic substrate, whether or not modified with such a polymeric fibrous material is preferably in an integral, uniform, woven or nonwoven, sheetlike condition. Preferably, individual substrate members are composed substantially of cellulose. The cellulosic fibers used in such a substrate member can be of natural or synthetic origin. Typical well-known sources for cellulose fibers include wood, cotton, and the like. Typically, and preferably, average fibers used in substrates employed in this invention have length to width ratios of at least about 2:1, and more preferably about 6:1, with maximum length to width ratios being variable.

The tenn substantially as used herein in reference to cellulosic substrates has reference to the fact that such a substrate comprises mainly cellulose fibers with not more than about to percent of any given cellulosic substrate being other components, such as nonfibrous fillers, diluents, and the like, or fibrous noncellulosic materials, such as those derived from organic sources, (e.g., protein, synthetic polymers like polyesters, etc.), or inorganic sources (e.g., silicious fibers or metallic fibers). Such other components when and if present characteristically have size ranges which are not greater in magnitude than the cellulosic fibers. Preferably, such other components are under I weight percent of the total weight of a starting individual cellulosic substrate member.

Particularly when high-electrical properties are desired in a product laminate of the invention, the cellulosic substrate member should have a low-ash content. Ash contents under 1 weight percent (based on total cellulosic substrate member weight) are preferred, and those having ash contents under 0.5 weight percent are more preferred.

When the impregnated cellulosic sheetlike products of this invention are to be used, for example, as battery separators, one class of preferred cellulosic nonwoven fibrous permeable structures have a Gurley porosity of about 1-25 seconds when using a 5 oz. cylinder and a '14; sq. in. orifice.

Before a liquid resole resin composition such as described above is used for impregnation of a preformed cellulosic substrate, it is convenient to dilute such composition with an organic liquid (as described above) so that the total solids concentration of such resulting composition typically ranges from about 5 to 40 weight percent (as indicated), with solids contents of 10 to 30 percent being preferred. A primary reason for impregnating with such an organic liquid is to permit one to impregnate a preformed cellulosic substrate such as paper without causing a deterioration in the wet strength thereof. By using an organic liquid system as described, the wet strength of a preformed cellulosic substrate material after impregnation and before drying to remove volatile liquid is maintained at convenient processing levels for subsequent drying, advancing, etc., by machines, etc.

In general, impregnation of a preformed substrate cellulosic member by such a resole composition can be accomplished by any conventional means, including spraying, dipping, coating, or the like, after which it is convenient and preferred to dry the so-treated sheet to remove residual volatile components and thereby leave a desired impregnated sheetlike construction. In drying, care is used to prevent excessive volatile material in the impregnated sheet. In general, a volatile level of less than about 8 percent by weight is preferred.

For purpose of this invention, volatile level is conveniently determined by loss in weight after 10 minutes at 160 C. of a sample impregnated sheet. A so impregnated sheet member generally contains from about 5 to 70 weight percent of solids derived from the substituted phenol-formaldehyde resole.

A preferred sheetlike product of this invention which is to be subsequently used in the manufacture of cellulosic laminates is advanced to an extent such that it has a flow of from about 3 to 20 percent (preferably from about 5 to percent). To so advance a sheet member to such a flow it is convenient to heat in air such an intermediate sheet to temperatures in the range of from about 30 to 180 C. for a time sufficient to advance same to the so-desired extent. It will be appreciated that such an advancement can be conveniently accomplished while residual volatile materials are being removed in a drying operation after impregnation, as indicated above.

Intermediate sheetlike members of this invention, whether advanced to the extent indicated or not, are generally at least about 4 mils thick and can be as thick as 20 mils, though thicknesses not more than about 10 mils are preferred.

The density of an individual impregnated sheetlike product is relatively unimportant since the laminate, as described below, is formed under heat and pressure conditions which,

generally solidify all components together into an integral, solid, nonporous, thermoset mass.

To make a laminate construction from an impregnated sheet member of this invention one forms at least one such sheet member (preferably advanced as described above) into a layered configuration which is at least two layers thick with adjoining layers being substantially in face-to-face engagement. As those skilled in the art will appreciate, an individual laminate construction of the invention can comprise a series of different impregnated cellulosic substrate members at least one of which is an intermediate sheetlike member of this invention or it can comprise a series of similar such intermediate members depending upon properties desired in the product laminate.

Such a layered configuration is then subjected to pressure in the range of from about 50 to 200 p.s.i. while maintaining temperatures in the range of from about to C. for a time sufficient to substantially completely thermoset the composite and thereby produce a desired laminate. Preferably the laminate is pressed at l40-160 C. at 500-1500 p.s.i. for 15-60 minutes. It is preferred to use sheet members of this invention as the sole components for laminates of this invention.

To make a battery separator from an impregnated sheet member of this invention one can initially treat a preformed fibrous nonwoven cellulosic sheet with a liquid resole resin composition as described above by either the wet-web saturation method or the dry-web method. In either method, it may be'desirable to dilute the resin composition in order to obtain the desired pickup. The impregnated cellulosic sheet is dried to remove excess solvent. This product sheet is then subjected to a temperature of about 200 to about 600 F. in order to cure the phenol-aldehye resin to an infusible substantially completely thermoset state. The time of exposure of the treated cellulosic fibrous sheet to these temperatures will vary from approximately 30 minutes at 200 F. to at least 1 minute at 600 F. In addition, the cellulosic fibrous battery separator is generally ribbed to increase its resistance to degradation during use thereof in a lead-acid battery. Generally, it is also desirable to impregnate the cellulosic fibrous sheet with about 20-50 weight percent of the resin composition of this invention.

Alternatively, the cellulosic fibrous sheet may be first treated with the phenol-aldehyde resin alone, and secondly, in a separate operation, treating the cellulosic fibrous sheet with the surface active agent either before or after subjecting the phenol-aldehyde treated fibrous sheet to the elevated temperatures.

The resole varnishes of this invention are useful in the manufacture of automotive oil filters. The cellulosic substrate employed in such filters is typically a cellulose fiber nonwoven paper modified with from about 1-50 weight percent of a synthetic organic fiber (such as a polyester or the like) and having a sheet thickness of from about 5 to 20 mils. Such a sheet is impregnated with sufficient resole varnish resin (as described above) according to this invention to obtain an impregnated sheet member having a resin content of about 15 to 25 percent, based on the weight of the total weight of the impregnated substrate. After the substrate is impregnated, it is heated to advance the resin to a Bstage (that is, until the impregnated substrate has a flow, say, of from about 3 to 20 percent) and then is conveniently corrugated or pleated (as those skilled in the art appreciate) to form the filter element. The filter element is then typically assembled into a filter container and heated to 250 to 350 F. for from to 20 minutes to cure the resin. The filter can be cured before such assembly. When cured, the product filter has good flexibility and good resistance to embrittlement after immersion in hot motor oil. Further, the B-staged impregnated paper has good tensile strength yet is flexible enough for processing into filter elements.

in general, to thermoset (cure) a cellulosic substrate impregnated with a substituted phenol-formaldehyde resin in accordance with the teachings of this invention, one conveniently heats the so-impregnated structure to a temperature ranging from about 200 to 350 F. for a time of from about 1 to 45 minutes, though lower and higher times and temperatures can be used.

EMBODIMENTS The following additional examples are set forth to illustrate more clearly the principles and practices of this invention to one skilled in the art, and they are not intended to be restrictive but merely to be illustrative of the invention herein contained. Unless otherwise stated herein, all parts and percentages are on a weight basis.

Examples of liquid-treating compositions suitable for use in making impregnated sheet members of this invention are as follows:

EXAMPLE A 100 Parts of phenol and 1 part of concentrated sulphuric acid are charged to a suitable reaction vessel and heated to 50 C. Then 70 parts of a carbocyclic compound mixture available commercially under the trade designation Monsanto Resin Oil having a composition as given in table 1 are added to the starting mixture while keeping the temperature stable at 50 C. The temperature of the mixture is held at 50 C. after addition of such carbocyclic compound mixture for 1 hour after which 7.5 cc. of 28 percent NH 0H is added thereto to neutralize the acid catalyst. To the neutralized reaction mixture 2 parts of triethylamine and 60 parts of 50 percent formalin (50-50 formaldehyde-water) are added and the reaction mixture is heated to a reflux at about l00 C. for 4 hours. Then the reaction mixture is cooled and volatile materials are removed under a vacuum of 28 inches of mercury until the temperature of the mixture rises to 80 C. Finally, 50 parts of methanol and parts of acetone are added to form a resin varnish treating solution having 71.4 percent solids (measured by heating 1 grams of resin for 3 hours at 135 C.), an Ostwald viscosity of 4,582 centipoises at 25 C., a pH of 8.42 and a water content of 1.76 percent.

XAMP E B in EXAMPLE C 100 Parts of phenol and 1 part of concentrated sulphuric acid are charged to a suitable reaction vessel. 50 Parts of the carbocyclic compound mixture used in example A are added to the mixture gradually over a period of 30 minutes. The temperature of the reaction mixture rises due to an exothermic reaction. The temperature of the mixture is held at 75 C. for 30 minutes and then 7.5 parts of 28 percent Nl-LOH are added to neutralize the acid catalyst. Next add 2 parts of triethylamine and 60 parts of 50 percent formalin are added to the neutralized mixture. Now the mixture is heated to a reflux at l00 C. for 2 hours. The mixture is cooled and volatile material (mainly water) is removed under a vacuum of 28 inches of mercury until the temperature of the mixture rises to 80 C. Finally, 60 parts of methanol are added to fonn a resin varnish-treating solution having a solids content of 68.5, percent a pH of 8.62, and a water content of 2 percent.

EXAMPLE D 100 Parts of phenol and l part of BF are charged to a suitable reaction vessel and heated to 50 C. 70 Parts of the carbocyclic compound mixture used in example A are added to the mixture. The temperature of the mixture is held at 50 C. for 1 hour after addition of such carbocyclic compound mixture and then 5.0 parts of NaOH are added to neutralize the acid catalyst. Next 60 parts of 50 percent formalin thereto and heat the resulting mixture to a reflux under vacuum at 66 C. and

. continue heating the mixture for 2 hours. Cool the mixture suitable reaction vessel and heated to 50 C. Then 30 parts of the carbocyclic compound mixture used in example A are added to the mixture gradually over a period of 30 minutes. The temperature of the mixture is held at 50 C. after addition of the carbocyclic compound mixture and then 7.5 parts of 28 a vacuum of 28 inches of mercury until the temperature of the mixture rises to 80 C. Finally, 50 parts of methanol are added to form a resin varnish-treating solution having a solids content of 68.5 percent, a pH of 8.62, and a water content of 2 percent.

EXAMPLES E THROUGH V The following examples are presented in tabular form for brevity. The process in all instances is as shown in example A except that the indicated variables are altered as shown in table IV below in each respective instance.

This intermediate product in each example is reacted with formaldehyde in the manner as taught in example A to produce first an aqueous resole emulsion product which is then treated in the same manner as taught in example A to reproduce a resole varnish.

In table IV, the numbers listed under Type Catalyst designate specific Friedel-Crafts catalysts, as follows:

2 BF -diethyl ether 3 p-toluene sulfonic acid 4 AlCl Similarly, the letters listed under type Carbocyclic Compound Mixture" each designate a specific carbocyclic composition as follows:

A B C D styrene l-2 [OJ 1 10 alpha-methyl styrene l-3 2.2 2 2 beta-methyl styrene l-3 2.1 2 2 vinyl toluene 14-2] 10.5 10 25 C, alkyl styrene 4-7 5.8 4 4 divinyl benzene l2 L6 1 l indene l5-22 l2.7 I0 25 methyl indene 4-7 7.6 5 5 dicyclopentadiene l2l8 1.1 5 25 rnethylcyclopentadiene 4-6 2.l l I inert diluent 25-35 44.2 59 0 The columns designated, respectively, Phenol," Amount Carbocyclic Compound Mixture," and "Amount Catalyst" are in terms of parts by weight.

TABLE IV Type Amount Post Catalyst carbocyclic carbocyclic Temperareaction compound compound ture, time, Phenol Type Amount mixture mixture C. min.

100 1 1. A 50 50 15 100 2 0.1 A 30 50 15 100 1 1. 0 A 50 75 15 100 2 1. 0 A 70 50 15 100 3 0. 5 A 30 65 100 1 0. 3 A 70 100 15 100 l 1. 0 A 30 100 15 100 l 0. 3 A 80 75 15 100 1 0. 3 B 90 75 45 100 1 0. 3 B 30 75 15 I00 4 1. 0 B 50 100 30 100 2 0. 5 B 70 50 15 100 1 0. 3 A 30 75 15 100 1 0.3 A 70 75 15 100 1 0. 3 C 50 75 15 100 1 0. 3 D 50 75 60 100 1 0. 3 C 125 85 15 100 l 0. 3 C 30 40 240 EXAMPLE W TABLE V One hundred parts of phenol and 0.3 part of concentrated Cured creenmnsl" content] strength flexes to sulphuric acid are charged to a suitable reaction vessel and varnish l fi| heated to 70 C. Seventy parts of the carbocyclic compound mixture used in example A are added to the mixture over a Exam le 1 zoo/8.5 l I90 Commercial l9.4/4.5 21.7 8

period of 45 minutes while keeping the temperature at 70-80 C. The temperature of the mixture is held at 70-80 C. after addition of the carbocyclic compound mixture for 15 minutes. The 3 parts of hexamethylene tetramine, 2 parts of triethylamine and 60 parts of 50 percent formalin (50-50 formaldehyde-water) are added to the reaction mixture. The reaction mixture is now heated to atmospheric reflux at 100 C. and refluxed for 2.5 hours. Then, the mixture is cooled, volatile material is removed under a vacuum of 25.5 inches of mercury until the temperature of the mixture reaches 60 C. Finally, 87 parts of methanol are added to form a resin treating solution having 59.3 percent solids (measured by heating 1.5 grams of resin for 3 hours at 135 C.) and an Ostward viscosity of 137 centipoises at 25C.

EXAMPLE X One hundred parts of phenol and 0.3 parts concentrated sulfuric acid are charged to a suitable reaction vessel and heated to 70 C. Seventy parts of carbocyclic compound mixture used in example A is added to the mixture over a period of 45 minutes while keeping the temperature at 70-80 C. The temperature of the mixture is held at 7080 C. after addition of the carbocyclic compound mixture for 15 minutes; then 3 parts of hexamethylenetetraethylamine, 2 parts of triethylamine and 60 parts of 50 percent fonnalin are added. The reaction mixture is heated to atmospheric reflux at 100 C. for 1.5 hours. The mixture is cooled, volatile material is removed under a vacuum of 25 kinches of mercury until the temperature of the mixture reaches 60 C. Finally, a 92/8 mixture of ethanol/toluene is added to form a resin treating solution having 66 percent solids.

Examples of impregnated cellulosic sheet members of this invention are as follows:

EXAMPLE 1 Two sheets of cellulose fiber paper containing 12 percent of a synthetic fiber (polyester) and having a thickness of 10 mils are separately impregnated with the varnish of example X and a commercial varnish to a cured resin content of about 20 percent by weight based on the weight of the paper. The impregnated sheets are heated to B-stage the resin and reduce the volatiles to from 4 to 10 percent. The filters are cured for about 15 minutes at about 300 F. The following Table sets forth comparative data for the varnish of this invention with a commercially available varnish.

"The force required to break 1 inch wide strips of the impregnated paper at B- stage.

After 2 hours conditioning in 300 F. oil.

The commercial varnish described above is about 60% solids in alcohol. has an al dehyde-to-phenol ratio of 1.75, and is made by condensing phenol and formaldehyde in the presence ofsodium hydroxide catalyst.

The above data show marked improvements in the flexibility of oil filter paper impregnated with modified phenolic resins in accordance with this invention over that obtainable with a commercially available resin.

EXAMPLES 232 Samples of preformed cellulosic substrate types are chosen as follows:

Type lNonwoven cotton linter paper, about l0 mils thick. Type 2Nonwoven unbleached Kraft paper about 7 mils thick.

Type 3Nonwoven a-cellulose paper about 10 mils thick.

Type 4Nonwoven bleached Kraft paper about 15 mils thick.

Type 5Woven cotton duck about 8 oz. weight.

Type 6-Woven linen cloth about 4 oz. weight.

Type 7-Nonwoven cellulose fiber paper containing 12 percent of a synthetic fiber (polyester) about 10 mils thick.

All types have an ash content less than about 0.9 weight percent.

The impregnation procedure for impregnating each above substrate is as follows: Preformed cellulosic sheets are passed through the impregnated solution diluted to the appropriate solids content, drawn through the nip region between a pair of squeeze rolls to remove excess resin and hung in an oven to dr l )etails are summarized in table VI below for each such product impregnated cellulose sheet of this invention:

TABLE VI cgnggugci Preformed Treating solution cellulose snb- Total Solids strata resin content type content 20 7 24 59 1 58 40 1 40 a 1 a 6 5 so 1 59 50 1 51 60 1 58 60 1 61 50 1 49 A 60 1 62 B 60 1 61 o 60 1 5s l) 60 1 60 l 00 l 01 I" till 1 llil u on 1 ml ll 00 1 ul) .I 00 i N tltl 0 on 1 as 1 (i0 1 6D 1t 60 1 59 S 60 1 60 T 1 60 The product nonthermoset intennediate resin impregnated cellulosic substrates are suitable for use in filter manufacture and for laminate manufacture. The product thcrmoset articles made from such intermediates display good tensile strength and flexibility characteristics.

What is claimed is:

l. A resin impregnated sheetlike form comprising:

A. a substrate member in sheet form comprising at least 50 weight percent cellulosic fibers with the balance up to l00 weight percent of any given such member being a synthetic organic polymeric fibrous material,

B. said substrate member being impregnated with from about 5 to 70 weight percent (based on total weight basis) of a substituted phenol-formaldehyde resole resin,

C. said resole resin being characterized by:

1. having a formaldehyde to phenol mol ratio of from about 0.8 to 2.0,

2. being produced by reacting under aqueous liquid phase conditions formaldehyde and a substituted phenol mixture in the presence of a basic catalyst,

3. being substantially insoluble in water but having a viscosity in methanol solution at 60 weight percent solids concentration of not greater than about 5,000 centipoises, and

4. having a free-formaldehyde content which is less than about 5 weight percent, 50

D. said substituted phenol mixture having been prepared by reacting phenol under Friedel-Crafts conditions with from about 10 to 80 parts by weight for each 100 parts by weight of said phenol of a mixture of carbocyclic compounds,

E. said mixture of carbocyclic compounds comprising (on a 100 weight percent basis when in a form substantially free of other materials):

1. from about 10 through 40 weight percent (total mixture basis) of compounds each molecule of which has: a. the indene nucleus,

b. from 9 through 13 carbon atoms,

c. as nuclear substitutents from 0 through 4 methyl groups,

2. from about 5 through 70 weight percent (total mixture basis) of compounds each molecule of which has:

a. the dicyclopentadiene nucleus,

b. from 10 through 13 carbon atoms,

c. as nuclear substituents from 0 through 3 methyl groups,

3. from about 15 through 65 weight percent (total mixture basis) of compounds each molecule of which has: a. a phenyl group substituted by a vinylidene group,

b. from 8 through 13 carbon atoms, c. as substitutents from 0 through 13 groups selected from the class consisting of methyl and ethyl,

4. from about 0 through 5 weight percent divinyl benzene,

5. provided that the sum total of all such compounds in any given such mixture of carbocyclic compounds is always weight percent.

2. The resin impregnated sheetlike form of claim 1 wherein said carbocyclic compound mixture comprises:

A. from about 20 through 40 weight percent (total mixture basis) of compounds each molecule of which has: 1. the indene nucleus 2. from 9 through 13 carbon atoms 3. as nuclear substituents from 0 through 4 methyl groups,

B. from about l5 through 30 weight percent (total mixture basis) of compounds each molecule of which has:

1. the dicyclopentadiene nucleus 2. from 10 through 13 carbon atoms,

3. as nuclear substituents from 0 through 3 methyl groups,

C. from about 30 through 65 weight percent (total mixture basis) of compounds each molecule of which has:

1. a phenyl group substituted by a vinylidene group,

2. from 8 through 13 carbon atoms,

3. as substituents from 0 through 3 groups selected from the class consisting of methyl and ethyl,

D. from about 0 through 5 weight percent divinyl benzene,

E. provided that the sum total of all such compounds in any given such mixture of carbocyclic compounds is always 100 weight percent.

3. The product of claim 1 wherein said resole resin is made by reacting said phenol and said mixture of carbocyclic com pounds in the presence of an inert hydrocarbon such that, of the combined weight of said mixture of carbocyclic compound and said inert hydrocarbon, the inert hydrocarbon portion thereof ranges from about 15 to 70 weight percent thereof.

4. The product of claim 1 wherein said substrate member is composed substantially of cellulose.

5. The product of claim 1 wherein said substrate member has an ash content under 0.5 weight percent.

6. A product of claim 1 which has a volatile level of less than about 8 percent by weight.

7. A product of claim 1 which is advanced to an extent such that it has a flow of from about 3 to 20 percent.

8. A product of claim 1 which is less than about 10 mils in thickness.

9. A product of claim 1 which is substantially completely thermoset.

.2 .A s s 

2. being produced by reacting under aqueous liquid phase conditions formaldehyde and a substituted phenol mixture in the presence of a basic catalyst,
 2. from about 5 through 70 weight percent (total mixture basis) of compounds each molecule of which has: a. the dicyclopentadiene nucleus, b. from 10 through 13 carbon atoms, c. as nuclear substituents from 0 through 3 methyl groups,
 2. The resin impregnated sheetlike form of claim 1 wherein said carbocyclic compound mixture comprises: A. from about 20 through 40 weight percent (total mixture basis) of compounds each molecule of which has:
 2. from 9 through 13 carbon atoms
 2. from 10 through 13 carbon atoms,
 2. from 8 through 13 carbon atoms,
 3. as substituents from 0 through 3 groups selected from the class consisting of methyl and ethyl, D. from about 0 through 5 weight percent divinyl benzene, E. provided that the sum total of all such compounds in any given such mixture of carbocyclic compounds is always 100 weight percent.
 3. The product of claim 1 wherein said resole resin is made by reacting said phenol and said mixture of carbocyclic compounds in the presence of an inert hydrocarbon such that, of the combined weight of said mixture of carbocyclic compound and said inert hydrocarbon, the inert hydrocarbon portion thereof ranges from about 15 to 70 weight percent thereof.
 3. as nuclear substituents from 0 through 3 methyl groups, C. from about 30 through 65 weight percent (total mixture basis) of compounds each molecule of which has:
 3. as nuclear substituents from 0 through 4 methyl groups, B. from about 15 through 30 weight percent (total mixture basis) of compounds each molecule of which has:
 3. from about 15 through 65 weight percent (total mixture basis) of compounds each molecule of which has: a. a phenyl group substituted by a vinylidene group, b. from 8 through 13 carbon atoms, c. as substitutents from 0 through 3 groups selected from the class consisting of mEthyl and ethyl,
 3. being substantially insoluble in water but having a viscosity in methanol solution at 60 weight percent solids concentration of not greater than about 5,000 centipoises, and
 4. having a free-formaldehyde content which is less than about 5 weight percent, D. said substituted phenol mixture having been prepared by reacting phenol under Friedel-Crafts conditions with from about 10 to 80 parts by weight for each 100 parts by weight of said phenol of a mixture of carbocyclic compounds, E. said mixture of carbocyclic compounds comprising (on a 100 weight percent basis when in a form substantially free of other materials):
 4. from about 0 through 5 weight percent divinyl benzene,
 4. The product of claim 1 wherein said substrate member is composed substantially of cellulose.
 5. The product of claim 1 wherein said substrate member has an ash content under 0.5 weight percent.
 5. provided that the sum total of all such compounds in any given such mixture of carbocyclic compounds is always 100 weight percent.
 6. A product of claim 1 which has a volatile level of less than about 8 percent by weight.
 7. A product of claim 1 which is advanced to an extent such that it has a flow of from about 3 to 20 percent.
 8. A product of claim 1 which is less than about 10 mils in thickness.
 9. A product of claim 1 which is substantially completely thermoset. 